Control Master uses a Master–Slave principle of operation. In all
systems there is one “Master Controller” board which is connected to a
computer via a standard USB lead and up to 30 slave boards. The job of
the Master is to allow the PC to send and receive data to any of the
slave boards. The Master Controller has an "on-board" RS485 driver which
provides the necessary signal conditioning to allow communications with
slave boards up to a massive 1Km (0.62 Miles) away from the controller.
The Master also has an on-board Microcontroller which is dedicated to
performing two main functions..

1. Handling the USB interface to the PC
2. Handling the RS485 serial communications to the
slave boards.

There are two different types of Master Controller available. The
“Non-isolated Master” is the simplest form offering a direct connection
between the PC the Master and the Slave boards. In this configuration
all of the boards share the same ground connection as the PC. In the
majority of applications this is perfectly acceptable. For info on the
fully isolated version click here

.

One of the few differences between the Isolated Master and the
Non-Isolated version is the power supply requirements. The Non-Isolated
master becomes fully operational as soon as you connect it to a USB
port. i.e. it receives all of its power from the USB port.

The Master simply connects to a slave by connecting two wires. These
wires are connected to terminals TL1 and are labelled A and B. Connect
the A on the Master to the A on the slave and similarly B to B. This
wire can be up to 1Km long and should be twisted wherever possible. The
signalling which takes place over this pair of wires is standard RS485
signals which are differential in nature. This means that they are
highly immune to electrical noise coming from the surroundings where the
cable is routed. Twisting the wires together improves this immunity by
making it less likely that an external electrical signal will cause any
differential interference voltage in the wires. Connecting to more than
one slave is simply a continuation of the two wire connection. This can
either be a separate two wires starting at the master and going, perhaps
in a different direction, to the second slave or it can be a connection
from slave one to slave two. In either case always ensure you connect
terminals A to A and B to B. The flexibility in forming a continuous
“chain” of slaves connected together and to the Master or to connect
them directly to the Master in a “star” configuration allows your wiring
to reflect the most suitable routing for your own application.
Also, remember that each slave can also be connected to other slaves in
a star configuration. The only limitation is that no slave can be any
more than 1Km from the Master in terms of total length of shortest cable
route. This flexibility makes the distributed control system very
suitable to a wide variety of installations

In particularly noisy (electrically) environments, such as heavy
industrial applications, it may be advisable to use additional shielding
for the pair of wires. In this case you can purchase commonly available
screened twisted pair cable which has the two wires plus an overall
metal foil screen, which is in turn covered in a plastic outer layer.
When using this type of cable the two wires should be connected as
normal and the metal foil screen should be connected to the terminal
marked “SCN” on the Master and on each slave.

(Note: This is not a "kit of parts" , it is fully assembled and tested)

Compatible with Windows XP,
Vista, 7, 8 and 10

To download a copy of the user
manual for this board, right click on the link on the
right and choose "save target as". This will allow you to
download a PDF copy of the manual

Manual

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is available for free download from Adobe using the link to the
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